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1G Stumbles at 5k

somanycarissues

Probationary Member
5
1
Jul 24, 2022
Washington
So I've had some issues with my 94 eclipse ever since I bought it about a month ago. The guy I bought it from said just needed the ecu fixed, so I sent it out and got it chipped and they said everything checked out to be good.

So the issue is stumbling at 5k at WOT and about 50% throttle I can make it to about 6k before stumbling. On my data logs I keep pulling code 21 for coolant sensor and the sensor is reading at 300-315 degrees which is what I'm thinking my issue is coming from and I have a backfire at idle but no miss.

I replaced the ect sensor and wired in the correct pigtail. I also installed a 2g maf since I read that the 1g has awful flow and I'm running a 16g turbo so I figured why not since I want to run more boost anyways.

While installing the new maf I notice the coolant level sensor in the overflow tank was unplugged so I plugged it in and when I went to start my car and nothing, I unplugged it again and started without any issue, and I've had all sorts of other unplugged connectors and spliced wires so I'm thinking of getting a new harness and just having that peace of mind of knowing all of my wires are good because I don't know where to look for the solution anymore.

If it's a fueling issue I have a walbro 255 pump I'm waiting to install once I get an FPR, but beyond that I'm lost. Any help is appreciated

Known goods:
Plugs are gapped to 0.028"
New NGK copper plugs and 7.5mm wires
New ect sensor and wiring correct (blk/grn to pcm signal, ylw/grn to 5v pos)
New 2g MAF
Good ECM with ECMLink

At this point seems like the dude may have swapped wires going into the back of the ecu
 
Last edited by a moderator:

steve

DSM Wiseman
14,720
1,588
Feb 3, 2002
Boulder, Colorado
Clearly the ECT sensor is off, it's hard to reach 300F with water and not have the radiator cap vent.

Your TPS is out of adjustment and your IPS isn't working (missing TB Ground?)
Your ECU never enters closed loop until 238 seconds in and as mentioned your knocking.

So fix the TPS, IPS, ECT, turn the IPS back on while moving in DSMLink.
When was the last time you did a boost leak test?
 

somanycarissues

Probationary Member
5
1
Jul 24, 2022
Washington
I honestly have no idea what is missing in terms of connections and grounds because the engine harness has been messed with a lot from the previous owner and I've spent my month owning this chasing down electrical issues. They had some off brand ect sensor so I got an oe one and wired it up properly but still a bad signal so idk if its grounding out early or wrong pin into the back of the ecu causing the sensor to read wrong, but in the log it shows cold start being at 160 already which is a bit below operating temps. The gauge works fine, and at work I've used one of the laser thermometers and everything reads out fine so I know my temps are in check. When I get a chance I'll look at the TPS and I know there's a slight boost leak at the TB but not big enough to cut all power and basically have the car fall on its face.

The knock sensor thinks its knocking when it stumbles, I've seen this in some of my other cars, which I know a bad ect sensor will has throw a code or readings for a knock sensor too since it doesn't get proper fuel and misses.

Would the best option at this point to be just getting a new harness since this one seems to be in really rough shape? Because I could chase these for another month and still be stuck here and at that point the $400 harness wouldn't look all that bad
 

AWD-Tony

Supporting Member
6,666
3,543
Sep 11, 2017
Cincinnati, Ohio
What Steve said! Did you install wire for NLTS? Looks like you have NLTS enabled and set to 5k. The log doesn't indicate you depressed the clutch once.
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I'm almost certain the clutch cut wire is not installed properly as you can see from injduty and rpm's bouncing at 5k.

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Which switch is it connected to? Correct switch would be the cruise control switch (away from the firewall).

 
Last edited:

AWD-Tony

Supporting Member
6,666
3,543
Sep 11, 2017
Cincinnati, Ohio
I honestly have no idea what is missing in terms of connections and grounds because the engine harness has been messed with a lot from the previous owner and I've spent my month owning this chasing down electrical issues. They had some off brand ect sensor so I got an oe one and wired it up properly but still a bad signal so idk if its grounding out early or wrong pin into the back of the ecu causing the sensor to read wrong, but in the log it shows cold start being at 160 already which is a bit below operating temps. The gauge works fine, and at work I've used one of the laser thermometers and everything reads out fine so I know my temps are in check. When I get a chance I'll look at the TPS and I know there's a slight boost leak at the TB but not big enough to cut all power and basically have the car fall on its face.

The knock sensor thinks its knocking when it stumbles, I've seen this in some of my other cars, which I know a bad ect sensor will has throw a code or readings for a knock sensor too since it doesn't get proper fuel and misses.

Would the best option at this point to be just getting a new harness since this one seems to be in really rough shape? Because I could chase these for another month and still be stuck here and at that point the $400 harness wouldn't look all that bad
If the harness is that hacked, yeah I would pick up a new one. This way you won’t have to worry about that going forward. I’m sure some of the wires are brittle now especially the part of the harness by the thermostat.
 

steve

DSM Wiseman
14,720
1,588
Feb 3, 2002
Boulder, Colorado
What Steve said! Did you install wire for NLTS? Looks like you have NLTS enabled and set to 5k. The log doesn't indicate you depressed the clutch once.
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I'm almost certain the clutch cut wire is not installed properly as you can see from injduty and rpm's bouncing at 5k.

Turn this off and see if the issue goes away.
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somanycarissues

Probationary Member
5
1
Jul 24, 2022
Washington
Thanks for all of the suggestions, I can't try them quite yet my trans started making some whining noises so I decided I need to rebuild it, but I've been looking for engine harnesses and can't find them anywhere, not even on Mitsubishi oem sites
 

Dericsh

Supporting Member
1,334
564
Nov 25, 2002
Pearl River, Louisiana
Thanks for all of the suggestions, I can't try them quite yet my trans started making some whining noises so I decided I need to rebuild it, but I've been looking for engine harnesses and can't find them anywhere, not even on Mitsubishi oem sites
No you’re going to have to make one yourself or spend a nice chunk at www.ohmracing.com
 
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